Techniques for simultaneously driving a plurality of source lines

ABSTRACT

Techniques for simultaneously driving a plurality of source lines are disclosed. In one particular exemplary embodiment, the techniques may be realized as an apparatus for simultaneously driving a plurality of source lines. The apparatus may include a plurality of source lines coupled to a single source line driver. The apparatus may also include a plurality of dynamic random access memory cells arranged in an array of rows and columns, each dynamic random access memory cell including one or more memory transistors. Each of the one or more memory transistors may include a first region coupled to a first source line of the plurality of source lines, a second region coupled to a bit line, a body region disposed between the first region and the second region, wherein the body region may be electrically floating, and a gate coupled to a word line and spaced apart from, and capacitively coupled to, the body region.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to semiconductor dynamic randomaccess memory (“DRAM”) devices and, more particularly, to techniques forsimultaneously driving a plurality of source lines (SL) in asemiconductor dynamic random access memory (“DRAM”) device.

BACKGROUND OF THE DISCLOSURE

There is a continuing trend to employ and/or fabricate advancedintegrated circuits using techniques, materials, and devices thatimprove performance, reduce leakage current, and enhance overallscaling. Semiconductor-on-insulator (SOI) is a material which may beused to fabricate such integrated circuits. Such integrated circuits areknown as SOI devices and may include, for example, partially depleted(PD) devices, fully depleted (FD) devices, multiple gate devices (forexample, double or triple gate), and Fin-FET devices.

One example of an SOI device is a semiconductor dynamic random accessmemory (“DRAM”) device. Such a semiconductor DRAM device may include anelectrically floating body in which electrical charges may be stored.The electrical charges stored in the electrically floating body mayrepresent a logic high or binary “1” data state or a logic low or binary“0” data state.

Various techniques may be employed to read data from and/or write datato a semiconductor DRAM device having an electrically floating body. Inone conventional technique, a memory cell having a memory transistor maybe read by applying a bias to a drain region of the memory transistor,as well as a bias to a gate of the memory transistor that is above athreshold voltage of the memory transistor. As such, conventionalreading techniques may sense an amount of channel currentprovided/generated in response to the application of the bias to thegate of the memory transistor to determine a state of the memory cell.For example, an electrically floating body region of the memory cell mayhave two or more different current states corresponding to two or moredifferent logical states (e.g., two different current conditions/statescorresponding to two different logic states: binary “0” data state andbinary “1” data state).

Also, conventional writing techniques for memory cells having anN-Channel type memory transistor typically result in an excess ofmajority charge carriers by channel impact ionization or by band-to-bandtunneling (gate-induced drain leakage “GIDL”). The majority chargecarriers may be removed via drain side hole removal, source side holeremoval, or drain and source hole removal, for example, using back gatepulsing.

Often, conventional reading and writing techniques may lead torelatively large power consumption and large voltage drivers whichoccupy large amount of area on a circuit board or die and causedisruptions to memory cells on unselected rows of an array of memorycells. Also, pulsing between positive and negative gate biases duringread and write operations may reduce a net quantity of charge carriersin an electrically floating body region of a memory cell in asemiconductor DRAM device, which, in turn, may gradually reduce, andeven eliminate a net charge representing data stored in the memory cell.In the event that a negative voltage is applied to a gate of a memorycell transistor, thereby causing a negative gate bias, a channel ofminority charge carriers beneath the gate may be eliminated. However,some of the minority charge carriers may remain “trapped” in interfacedefects. Some of the trapped minority charge carriers may recombine withmajority charge carriers, which may be attracted to the gate, and a netcharge associated with majority charge carriers located in theelectrically floating body region may decrease over time. Thisphenomenon may be characterized as charge pumping, which is a problembecause the net quantity of charge carriers may be reduced in anelectrically floating body region of the memory cell, which, in turn,may gradually reduce, and even eliminate, a net charge representing datastored in the memory cell.

In view of the foregoing, it may be understood that there aresignificant problems and shortcomings associated with reading fromand/or writing to electrically floating body semiconductor dynamicrandom access memory (“DRAM”) devices using conventional reading/writingtechniques.

SUMMARY OF THE DISCLOSURE

Techniques for simultaneously driving a plurality of source lines (SL)are disclosed. In one particular exemplary embodiment, the techniquesmay be realized as an apparatus for simultaneously driving a pluralityof source lines. The apparatus may comprise a plurality of source linescoupled to a single source line driver. The apparatus may also comprisea plurality of dynamic random access memory cells arranged in an arrayof rows and columns, each dynamic random access memory cell includingone or more memory transistors. Each of the one or more memorytransistors may comprise a first region coupled to a first source lineof the plurality of source lines, a second region coupled to a bit line,a body region disposed between the first region and the second region,wherein the body region may be electrically floating, and a gate coupledto a word line and spaced apart from, and capacitively coupled to, thebody region.

In accordance with other aspects of this particular exemplaryembodiment, a total number of source lines coupled to the source linedriver may be based at least in part on power consumption of theplurality of dynamic random access memory cells.

In accordance with further aspects of this particular exemplaryembodiment, a total number of source lines coupled to the source linedriver may be based at least in part on disturbance on the plurality ofdynamic random access memory cells.

In accordance with additional aspects of this particular exemplaryembodiment, each row of the plurality of dynamic random access cells maybe coupled to one source line of the plurality of source lines.

In accordance with other aspects of this particular exemplaryembodiment, multiple rows of the plurality of dynamic random accessmemory cells may be coupled to one source line of the plurality ofsource lines.

In accordance with further aspects of this particular exemplaryembodiment, at least one of four source lines, eight source lines,sixteen source lines, or thirty-two source lines may be coupled to thesource line driver.

In accordance with additional aspects of this particular exemplaryembodiment, the plurality of source lines may be divided into aplurality of sub-groups of source lines.

In accordance with yet another aspect of this particular exemplaryembodiment, each of the plurality of sub-groups of source lines may beconfigured to perform at least one of a plurality of operations.

In accordance with other aspects of this particular exemplaryembodiment, the plurality of operations may comprise at least one of awrite operation, a read operation, a refresh operation, and an inhibitoperation.

In accordance with further aspects of this particular exemplaryembodiment, each of the plurality of sub-groups of source lines may beconfigured to perform different operations of the plurality ofoperations.

In another particular exemplary embodiment, the techniques may berealized as a method for simultaneously driving a plurality of sourcelines. The method may comprise coupling a plurality of source lines to asource line driver. The method may also comprise arranging a pluralityof dynamic random access memory cells in an array of rows and columns,each dynamic random access memory cell including one or more memorytransistors. Each of the one or more transistors may comprise a firstregion coupled to a first source line of the plurality of source lines,a second region coupled to a bit line, a body region disposed betweenthe first region and the second region, wherein the body region iselectrically floating, and a gate coupled to a word line and spacedapart from, and capacitively coupled to, the body region.

In accordance with other aspects of this particular exemplaryembodiment, the method for simultaneously driving a plurality of sourcelines may further comprise coupling each row of the plurality of dynamicrandom access cells to one source line of the plurality of source lines.

In accordance with additional aspects of this particular exemplaryembodiment, the method for simultaneously driving a plurality of sourcelines may further comprise coupling multiple rows of the plurality ofdynamic random access memory cells to one source line of the pluralityof source lines.

In accordance with another aspect of this particular exemplaryembodiment, coupling a plurality of source lines to a source line drivermay comprise coupling at least one of four source lines, eight sourcelines, sixteen source lines, or thirty-two source lines to the sourceline driver.

In accordance with other aspects of this particular exemplaryembodiment, the plurality of source lines may be divided into aplurality of sub-groups of source lines.

In accordance with further aspects of this particular exemplaryembodiment, each of the plurality of sub-groups of source lines may beconfigured to perform at least one of a plurality of operations.

In accordance with additional aspects of this particular exemplaryembodiment, the plurality of operations may comprise at least one of awrite operation, a read operation, a refresh operation, and an inhibitoperation.

In accordance with another aspect of this particular exemplaryembodiment, each of the plurality of sub-groups of source lines may beconfigured to perform different operations of the plurality ofoperations.

The present disclosure will now be described in more detail withreference to exemplary embodiments thereof as shown in the accompanyingdrawings. While the present disclosure is described below with referenceto exemplary embodiments, it should be understood that the presentdisclosure is not limited thereto. Those of ordinary skill in the arthaving access to the teachings herein will recognize additionalimplementations, modifications, and embodiments, as well as other fieldsof use, which are within the scope of the present disclosure asdescribed herein, and with respect to which the present disclosure maybe of significant utility.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a fuller understanding of the present disclosure,reference is now made to the accompanying drawings, in which likeelements are referenced with like numerals. These drawings should not beconstrued as limiting the present disclosure, but are intended to beexemplary only.

FIG. 1A shows a cross-sectional view of a memory cell in accordance withan embodiment of the present disclosure.

FIG. 1B shows a schematic representation of a portion of a semiconductorDRAM device including a plurality of memory cells arranged in arrays ofrows and columns in accordance with an embodiment of the presentdisclosure.

FIGS. 2A and 2B show charge relationships, for given data states, of amemory cell in accordance with an embodiment of the present disclosure.

FIG. 3 shows schematic a block diagram of a semiconductor DRAM device inaccordance with an embodiment of the present disclosure.

FIG. 4 shows an exemplary embodiment of a memory array having aplurality of memory cells and employing a separate source lineconfiguration for each row of memory cells in accordance with anembodiment of the present disclosure.

FIG. 5 shows a diagram of voltage control signals to implement a writeoperation for logic high or binary “1” data state into a memory cell inaccordance with an embodiment of the present disclosure.

FIG. 6 shows a diagram of voltage control signals to implement a writeoperation for logic low or binary “0” data state into a memory cell inaccordance with an embodiment of the present disclosure.

FIG. 7 shows a diagram of voltage control signals to implement a readoperation of a memory cell in accordance with an embodiment of thepresent disclosure.

FIG. 8 shows a schematic of a memory array implementing the structureand techniques having a common source line in accordance with anembodiment of the present disclosure.

FIG. 9 shows a diagram of voltage control signals to implement a writeoperation for logic high or binary “1” data state into a memory cell inaccordance with an embodiment of the present disclosure.

FIG. 10 shows a diagram of voltage control signals to implement a writeoperation for logic low or binary “0” data state into a memory cell inaccordance with an embodiment of the present disclosure.

FIG. 11 shows a diagram of voltage control signals to implement a readoperation of a memory cell in accordance with an embodiment of thepresent disclosure.

FIG. 12 shows a diagram of voltage control signals to implement a writeoperation, a read operation, a refresh operation and/or an inhibitoperation into a memory cell in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

There are many embodiments described and illustrated herein. In oneaspect, the present disclosure is directed to a combination ofreading/writing methods which comprise simultaneously driving aplurality of source lines (SL). Also, the present disclosure is directedto providing a relatively high voltage when reading from and/or writingto memory cells so as to reduce disruptions to unselected memory cellsand increase retention time.

Referring to FIG. 1A, there is a shown a cross-sectional view of amemory cell 12 in accordance with an embodiment of the presentdisclosure. The memory cell 12 may comprise a memory transistor 14(e.g., an N-channel type transistor or a P-channel type transistor)including a source region 20, a drain region 22, and an electricallyfloating body region 18 disposed between the source region 20 and thedrain region 22. Charge carriers 34 may be accumulated in or may beemitted/ejected from the electrically floating body region 18. A datastate of the memory cell 12 may be defined by an amount of chargecarriers 34 present in the electrically floating body region 18.

The memory transistor 14 may also include a gate 16 disposed over theelectrically floating body region 18. An insulating film 17 may bedisposed between the gate 16 and the electrically floating body region18. Moreover, the electrically floating body region 18 may be disposedon or above region 24, which may be an insulation region (e.g., in anSOI material/substrate) or a non-conductive region (e.g., in a bulk-typematerial/substrate). The insulation or non-conductive region 24 may bedisposed on a substrate 26.

Referring to FIG. 1B, there is shown a schematic representation of aportion 10 of a semiconductor DRAM device including a plurality ofmemory cells 12 arranged in an array of rows and columns in accordancewith an embodiment of the present disclosure. The semiconductor DRAMdevice portion 10 also includes a plurality of word lines 28 (WL), aplurality of source lines 30 (SL), and a plurality of bit lines 32 (BL),each electrically coupled to corresponding ones of the plurality ofmemory cells 12. Each memory cell 12 may include a memory transistor 14,as described above with reference to FIG. 1A, wherein the memorytransistor 14 may include a source region 20 coupled to an associatedsource line 30 (SL), a drain region 22 coupled to an associated bit line32 (BL), and an electrically floating body region 18 disposed betweenthe source region 20 and the drain region 22. The memory transistor 14may also include a gate 16 disposed over the electrically floating bodyregion 18 and coupled to an associated word line 28 (WL). In anexemplary embodiment, the source region 20 of the memory transistor 14of each memory cell 12 of a first row of memory cells 12 may be coupledto a first source line 30 (SL). Also, the source region 20 of the memorytransistor 14 of each memory cell 12 of a second row of memory cells 12may be coupled to the first source line 30 (SL). In another exemplaryembodiment, the source region 20 of the memory transistor 14 of eachmemory cell 12 of a second row of memory cells 12 may be coupled to asecond source line 30 (SL), and the source region 20 of the memorytransistor 14 of each memory cell 12 of a third row of memory cells maybe coupled to a third source line 30 (SL).

Data may be written into a selected memory cell 12 of the semiconductorDRAM device portion 10 by applying suitable control signals to aselected word line 28, a selected source line 30, and/or a selected bitline 32. The memory cell 12 may exhibit (1) a first data state which isrepresentative of a first amount of charge carriers 34 in theelectrically floating body region 18 of the memory transistor 14, and(2) a second data state which is representative of a second amount ofcharge carriers 34 in the electrically floating body region 18 of thememory transistor 14. Additional data states are also possible.

The semiconductor DRAM device portion 10 may further include data writecircuitry (not shown), coupled to the memory cell 12, to apply (i) firstwrite control signals to the memory cell 12 to write the first datastate therein and (ii) second write control signals to the memory cell12 to write the second data state therein. In response to the firstwrite control signals applied to the memory cell 12, the memorytransistor 14 may generate a first transistor current which maysubstantially provide a first charge in the electrically floating bodyregion 18 of the memory transistor 14. In this case, charge carriers 34may accumulate in or may be emitted/ejected from the electricallyfloating body region 18. As discussed above, a data state may be definedby an amount of charge carriers 34 present in the electrically floatingbody region 18. For example, the amount of charge carriers 34 present inthe electrically floating body region 18 may represent a logic high(i.e., binary “1” data state) or a logic low (i.e., binary “0” datastate). Additional data states are also possible.

The first write control signals may include a signal applied to the gate16 and a signal applied to the source region 20, wherein the signalapplied to the source region 20 may include a first voltage potentialhaving a first amplitude and a second voltage potential having a secondamplitude. In another exemplary embodiment, the first write controlsignals may include a signal applied to the gate 16 and a signal appliedto the drain region 22, wherein the signal applied to the drain region22 may include a third voltage potential having a third amplitude and afourth voltage potential having a fourth amplitude.

Also, the second write signals may include a signal applied to the gate16, a signal applied to the source region 20, and a signal applied tothe drain region 22. The signal applied to the drain region 22 mayinclude a block voltage potential to prevent the first data state andsecond data state from being written into the memory transistor 14.

Referring to FIGS. 2A and 2B, there are shown charge relationships, forgiven data states, of the memory cell 12 in accordance with anembodiment of the present disclosure. In an exemplary embodiment, eachmemory cell 12 of the semiconductor DRAM device portion 10 may operateby accumulating or emitting/ejecting majority charge carriers 34 (e.g.,electrons or holes) in/from the electrically floating body region 18.FIGS. 2A and 2B illustrate this with an N-Channel memory transistor 14.More specifically, various write techniques may be employed toaccumulate majority charge carriers 34 (in this example, holes) in theelectrically floating body region 18 of the memory cell 12 by, forexample, impact ionization near the source region 20 and/or drain region22 (see FIG. 2A). Also, the majority charge carriers 34 may be emittedor ejected from the electrically floating body region 18 by, forexample, forward biasing a junction between the source region 20 and theelectrically floating body region 18 and/or a junction between the drainregion 22 and the electrically floating body region 18 (see FIG. 2B).

As shown in FIG. 2A, a logic high (binary “1” 1 data state) maycorrespond to an increased concentration of majority charge carriers 34in the electrically floating body region 18 relative to an unwrittenmemory cell 12 and/or a memory cell 12 that is written with a logic low(binary “0” data state). In contrast, as shown in FIG. 2B, a logic low(binary “0” data state) may correspond to a reduced concentration ofmajority charge carriers 34 in the electrically floating body region 18relative to an unwritten memory cell 12 and/or a memory cell 12 that iswritten with a logic high (binary “1” data state).

The semiconductor DRAM device portion 10 may further include data sensecircuitry (not shown), coupled to the memory cell 12, to sense a datastate of the memory cell 12. More specifically, in response to readcontrol signals applied to the memory cell 12, the memory transistor 14may generate a second transistor current that is representative of adata state of the memory cell 12. The data sense circuitry may determinea data state of the memory cell 12 based at least substantially on thesecond transistor current.

The read control signals may include signals applied to the gate 16,source region 20, and drain region 22 to cause, force, and/or induce thesecond transistor current, which is representative of a data state ofthe memory cell 12. The read control signals applied to the gate 16,source region 20, and drain region 22 may include a positive voltage ora negative voltage. One or more of the read control signals may includea constant or unchanging voltage amplitude.

Referring to FIG. 3, there is shown a schematic block diagram of asemiconductor DRAM device 300 in accordance with an embodiment of thepresent disclosure. The semiconductor DRAM device 300 may include amemory cell array 302, data write and sense circuitry 36, memory cellselection and control circuitry 38, reference current generationcircuitry 40, and input/output circuitry 42. The memory cell array 302may include a plurality of memory cells 12 arranged in a matrix of rowsand columns including a plurality of word lines 28 (WL), a plurality ofsource lines 30 (SL), and a plurality of bit lines 32 (BL). The memorycell array 302 may be coupled to the memory cell selection and controlcircuitry 38 via the word lines 28 (WL) and/or the source lines 30 (SL).Also, the memory cell array 302 may be coupled to the data write andsense circuitry 36 via the bit lines 32 (BL).

In an exemplary embodiment, the data write and sense circuitry 36 mayinclude a plurality of data sense amplifier circuitry 44 and a pluralityof reference current input circuitry 46. Each data sense amplifiercircuitry 44 may receive at least one bit line (BL) 32 and the output ofreference current generator circuitry 40 (for example, a current orvoltage reference signal) via a corresponding reference current inputcircuitry 46. For example, each data sense amplifier circuitry 44 may bea cross-coupled type of sense amplifier to detect, determine, sense,and/or sample a data state of a memory cell 12. Each data senseamplifier circuitry 44 may detect a data state of one or more memorycells 12 (e.g., along bit lines 32 a-32 x (BEL)) by comparing voltagesor currents on a bit line (BL) 32 with voltages or currents of theoutput of the reference current generator circuitry 40. Also, apredetermined voltage may be applied to the bit lines 32 (BL) based atleast in part on a data state determined by the data sense amplifiercircuitry 44 to write-back the data state into memory cell 12.

The data sense amplifier circuitry 44 may employ voltage and/or currentsensing circuitry and/or techniques. In an exemplary embodiment, thedata sense amplifier circuitry 44 may employ a current sensing circuitryand/or techniques, the current sense amplifier circuitry 44 may comparethe current from the selected memory cell 12 to a reference current fromthe reference current input circuitry 46, for example, the current ofone or more reference cells. From that comparison, it may be determinedwhether memory cell 12 contained a logic high (binary “1” data state,relatively more majority charge carriers 34 contained within the bodyregion 18) or a logic low (binary “0” data state, relatively lessmajority charge carriers 34 contained within the body region 18). It maybe appreciated by one having ordinary skill in the art, any type or formof data write and sense circuitry 36 (including one or more senseamplifiers, using voltage or current sensing techniques, to sense thedata state stored in memory cell 12) to read the data stored in memorycells 12 and/or write data in memory cells 12 may be employed.

The memory cell selection and control circuitry 38 may select and/orenable one or more predetermined memory cells 12 to facilitate readingdata therefrom and/or writing data thereto by applying control signalson one or more word lines 28 (WL) and/or source lines 30 (SL). Thememory cell selection and control circuitry 38 may generate such controlsignals using address data, for example, row address data. Moreover,memory cell selection and control circuitry 38 may include a word linedecoder and/or driver (not shown). For example, memory cell selectionand control circuitry 38 may include one or more differentcontrol/selection techniques (and circuitry therefor) to implement thememory cell selection technique. Such techniques, and circuitrytherefor, are well known to those skilled in the art. Notably, all suchcontrol/selection techniques, and circuitry therefor, whether now knownor later developed, are intended to fall within the scope of the presentdisclosures.

In an exemplary embodiment, the semiconductor DRAM device 300 mayimplement a two step write operation whereby all the memory cells 12 ofa given row are written to a predetermined data state by first executinga “clear” operation, whereby all of the memory cells 12 of the given rowmay be written to logic low (binary “0” data state) and thereafterselected memory cells 12 of the row may be selectively written to thepredetermined data state (here logic high (binary “1” data state)). Thepresent disclosure may also be implemented in conjunction with a onestep write operation whereby selective memory cells 12 of the selectedrow are selectively written to either logic high (binary “1” data state)or logic low (binary “0” data state) without first implementing a“clear” operation.

The memory cell array 10 may employ any of the exemplary writing,holding, and/or reading techniques described herein. Moreover, exemplaryvoltage values for each of the control signals for a given operation(for example, writing, holding or reading), according to exemplaryembodiments of the present disclosure, is also provided.

The memory transistors 14 may be comprised of N-channel, P-channeland/or both types of transistors. Indeed, circuitry that is peripheralto the memory array (for example, sense amplifiers or comparators, rowand column address decoders, as well as line drivers (not illustratedherein) may include P-channel and/or N-channel type transistors. In theevent that P-channel type transistors are employed as memory transistors14 in the memory cell(s) 12, suitable write and read voltages (forexample, negative voltages) are well known to those skilled in the artin light of this disclosure. Accordingly, for sake of brevity, thesediscussions will not be repeated.

Referring to FIG. 4, there is shown an exemplary embodiment of a memoryarray 40 having a plurality of memory cells 12 and a separate sourceline configuration for each row of memory cells 12 in accordance with anembodiment of the present disclosure. The plurality of memory cells 12include a sub-array of memory cells 12 (for example, 8×8 sub-array ofmemory cells 12 enclosed by the dotted line). The semiconductor DRAMdevice 10 may include data write and sense circuitry 36 coupled to aplurality of bit lines 32 (BL) of the plurality of memory cells 12 (forexample, 32 _(j), 32 _(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+4), 32 _(j+5),32 _(j+6), and 32 _(j+7)). Also, the semiconductor DRAM device 10 mayinclude memory cell selection and control circuitry 38 coupled to aplurality of word lines 28 (WL) (for example, 28 _(i), 28 _(i+1), 28_(i+2), 28 _(i+3), 28 _(i+4), 28 _(i+5), 28 _(i+6), and 28 _(i+7))and/or a plurality of source lines 30 (SL) (for example, 30 _(i), 30_(i+1), 30 _(i+2), 30 _(i+3), 30 _(i+4), 30 _(i+5), 30 _(i+6), and 30_(i+7)). In an exemplary embodiment, the source lines 30 (SL) (forexample, 30 _(i), 30 _(i+1), 30 _(i+2), 30 _(i+3), 30 _(i+4), 30 _(i+5),30 _(i+6), and 30 _(i+7)) of the sub-array of memory cells 12 may becoupled together and driven by a source line driver 48 (e.g., invertercircuits and/or logic circuits). Although the source line driver 48shown in FIG. 4, may be an independent voltage driver, the source linedriver 48 may be located within and/or integrated with the memory cellselection and control circuitry 38. Therefore, an amount of space takenby source line drivers 48 in the semiconductor DRAM device 10 may bereduced by coupling a plurality of source lines (SL) 30 of a sub-arrayof memory cells 12 to a single source line driver 48.

As illustrated in FIG. 4, a sub-array of memory cells 12 of thesemiconductor DRAM device 10 may include eight rows by eight columns ofmemory cells 12 having a plurality of source lines (SL) coupled to asingle source line (SL) driver. It may be appreciated by one skilled inthe art that the size of the sub-array of memory cells 12 having aplurality of source lines (SL) coupled to a single source line (SL)driver may vary, for example symmetrical sub-array, but not limited to,four rows by four columns, sixteen rows by sixteen columns, thirty-tworows by thirty-two columns, sixty-four rows by sixty-four columns, etc.Also, the sub-array of memory cells 12 may be asymmetrical sub-array,for example, but not limited to, four rows by third-two columns, eightrows by four columns, sixteen rows by thirty-two columns, etc.

In an exemplary embodiment, several factors may determine the size of asub-array of memory cells 12 of the semiconductor DRAM device 10including a plurality of source lines (SL) coupled to a single sourceline (SL) driver. A power consumption of the semiconductor DRAM device10 may determine a size of a sub-array of memory cells 12 including aplurality of source lines (SL) coupled to a single source line (SL)driver. For example, a sixteen rows by sixteen columns sub-array ofmemory cells 12 may consume more power compared to a four rows by fourcolumns sub-array of memory cells 12 because a greater number of sourcelines (SL) are coupled together. The source line (SL) driver may consumemore power (for example, applying higher voltage) by driving a greaternumber of source lines (SL) coupled together between a high voltage anda low voltage to perform various operations (for example, read, write,refresh, and/or inhibit). Also by coupling a greater number of sourcelines (SL) together, the source line (SL) driver may apply a highervoltage to drive the greater number of source lines (SL) and may consumemore power because a thicker gauged wire and/or metal plate may benecessary in order to withstand the high voltage applied by the sourceline (SL) driver.

Also, disturbance (e.g., influence a data state stored on a memory cell12) on one or more unselected source lines (SL) may determine a size ofa sub-array of memory cells 12 including a plurality of source line (SL)coupled to a single source line (SL) driver. For example, the sourceline (SL) driver may apply a voltage to a plurality of coupled sourcelines (SL) to perform a read and/or a write operations. Although, asingle row may be selected for a read and/or a write operations, allcoupled source lines (SL) may receive a voltage applied by the sourceline (SL) driver. Therefore, one or more memory cells 12 coupled to theunselected source lines (SL) may be disturbed (e.g., influence an amountof charged stored in the memory cells 12) by a voltage applied by thesource line (SL) driver.

In addition, an amount of area on a circuit board or die available forsource line (SL) drivers may determine a size of a sub-array of memorycells 12 including a plurality of source line (SL) coupled to the sourceline (SL) drivers. For example, a small amount of area on a circuitboard or die may be available to accommodate source line (SL) drivers.Thus, a small number of source line (SL) drivers may be placed on thecircuit board or die and a number of source lines (SL) coupled to thesource line (SL) drivers may increase. Also, a large amount of area on acircuit board or die may be available to accommodate source line (SL)drivers. Thus, a large number of source line (SL) drivers may be placedon the circuit board or die and a number of source lines (SL) coupled tothe source line (SL) drivers may decrease.

In an exemplary embodiment, memory cells 12 may be written using a twostep operation wherein a given row of memory cells 12 are written to afirst predetermined data state by first executing a “clear” operation(which, in this exemplary embodiment, a selected row 28 _(i) and/or allof the memory cells 12 of the given row are written or programmed tologic low (binary “0” l date state)) and thereafter selected memorycells 12 may be written to a second predetermined data state (i.e., aselective write operation to the second predetermined data state). The“clear” operation may be performed by writing each memory cell 12 of thegiven row to a first predetermined data state (in this exemplaryembodiment the first predetermined data state is logic low (binary “0”data state) using the inventive technique described above.

In particular, memory transistor 14 of each memory cell 12 of a givenrow (for example, memory cells 12 a-12 h) is controlled to store amajority charge carrier concentration in the electrically floating bodyregion 18 of the transistor 14 which corresponds to a logic low (binary“0” data state). For example, control signals to implement a “clear”operation may be applied to the gate 16, the source region 20, and thedrain region 22 of the memory transistor 14 of memory cells 12 a-12 h.In an exemplary embodiment, a “clear operation” includes applying (i)1.5V to the gate 16, (ii) 0V to the source region 20, and (iii) 0V tothe drain region 22 of the memory transistor 14. In response, the samelogic state (for example, logic low (binary “0” data state)) may bestored in memory cells 12 a-12 h and the state of memory cells 12 a-12 hmay be “cleared”. For example, it may be preferable to maintain thegate-to-source voltage below the threshold voltage of the transistor ofmemory cell 12 to further minimize or reduce power consumption.

Thereafter, selected memory cells 12 of a given row may be written tothe second predetermined logic state. For example, the memorytransistors 14 of certain memory cells 12 of a given row may be writtento the second predetermined logic state in order to store the secondpredetermined logic state in memory cells 12. For example, memory cells12 a and 12 e may be written to logic high (binary “1” data state) (asshown in the selected row 28 _(i)), via an impact ionization effectand/or avalanche multiplication, by applying (i) −2.0V to the gate (viaword line 28 _(i)), (ii) −2.0V to the source region (via source line 30_(i)), and (iii) 1.5V to the drain region (via bit line 32 _(j) and 32_(j+4)). Particularly, such control signals may generate or provide abipolar current in the electrically floating body region 18 of thememory transistor 14 of memory cells 12 a and 12 e. The bipolar currentmay cause or produce impact ionization and/or the avalanchemultiplication phenomenon in the electrically floating body region 18 ofthe memory transistors 14 of memory cells 12 a and 12 e. In this way, anexcess of majority charge carriers may be provided and stored in theelectrically floating body region 18 of the memory transistor 14 ofmemory cells 12 a and 12 e which corresponds to logic high (binary “1”data state).

In an exemplary embodiment, memory cells 12 b, 12 c, 12 d, 12 f, 12 g,and 12 h (as shown in the selected row 28 _(i)) may be maintained atlogic low (binary “0” data state) by applying a voltage to inhibitimpact ionization to the drain region 22 of each memory cell 12 b, 12 c,12 d, 12 f, 12 g, and 12 h. For example, applying 1V to the drainregions 22 of memory cells 12 b, 12 c, 12 d, 12 f, 12 g, and 12 h (viabit lines 32 _(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32_(j+7)) may inhibit impact ionization in memory cells 12 b, 12 c, 12 d,12 f, 12 g, and 12 h during the selective write operation for memorycells 12 a, and 12 e.

Also, memory cells 12 (as shown in the selected row 28 _(i)) may beselectively written to logic high (binary “1” data state) using theband-to-band tunneling (GIDL) method. As mentioned above, theband-to-band tunneling provides, produces and/or generates an excess ofmajority charge carriers in the electrically floating body 18 of thememory transistors 14 of each selected memory cell 12 (in this exemplaryembodiment, memory cells 12 a and 12 e). For example, after implementingthe “clear” operation, memory cells 12 a and 12 e may be written tologic high (binary “1” data state), via band-to-band tunneling, byapplying (i) −3V to the gate 16 (via word line 28 _(i)), (ii) −0.5V tothe source region 20 (via source line 30 _(i)), and (iii) 1.0V to thedrain region 22 (via bit line 32 _(j) and 32 _(j+4)).

A selected row of memory cells 12 may be read by applying read controlsignals to the associated word line (WL) 28 and associated source lines(SL) 30 and sensing a signal (voltage and/or current) on associated bitlines (EL) 32. In an exemplary embodiment, memory cells 12 a-12 h (e.g.,as shown in the selected row 28 _(i)) may be read by applying (i) −0.5Vto the gate 16 (via word line 28 _(i)), (ii) 2.5V to the source region20 (via source lines 30 coupled to a single source line driver) and(iii) 0V to the drain region 22 (via bit lines 32). The data write andsense circuitry 36 may read the data state of the memory cells 12 a-12 hby sensing the response to the read control signals applied to word line28 _(i), source line 30 and bit line 32. In response to the read controlsignals, memory cells 12 a-12 h may generate a bipolar transistorcurrent which may be representative of the data state of memory cells 12a-12 h. For example, memory cells 12 a and 12 e (which were earlierwritten to logic high (binary “1” data state)), in response to the readcontrol signals, may generate a bipolar transistor current which isconsiderably larger than any channel current. In contrast, memory cells12 b, 12 c, 12 d, 12 f, 12 g, and 12 h (which were earlier programmed tologic low (binary “0” data state)), such control signals induce, causeand/or produce little to no bipolar transistor current (for example, aconsiderable, substantial or sufficiently measurable bipolar transistorcurrent). The circuitry in data write and sense circuitry 36 to sensethe data state (for example, a cross-coupled sense amplifier) senses thedata state using primarily and/or based substantially on the bipolartransistor current.

Thus, in response to read control signals, the memory transistor 14 ofeach memory cell 12 a-12 h may generate a bipolar transistor currentwhich is representative of the data state stored therein. The datasensing circuitry in data write and sense circuitry 36 may determine thedata state of memory cells 12 a-12 h based substantially on the bipolartransistor current induced, caused and/or produced in response to theread control signals.

FIG. 5 shows a diagram of voltage control signals to implement a writeoperation for logic high (binary “1” data state) into a memory cell inaccordance with an exemplary embodiment of the present disclosure. Thecontrol signals may be configured to reduce a number of source line (SL)drivers by coupling a plurality of source lines (SL) to a single sourceline (SL) driver as well as a one step write whereby selected memorycells 12 of a selected row of memory cells 12 may be selectively writtenor programmed to either logic high (binary “1” data state) or logic low(binary “0” date state) without first implementing a “clear” operation.For example, the temporally varying control signals to implement thewrite logic high (binary “1” data state) operation include the voltageapplied to the gate 16 (V_(gw“1”)), the voltage applied to the sourceregion 20 (V_(sw“1”)), and the voltage applied to the drain region 22(V_(dw“1”)). The binary “1” or “0” data states may be written to one ormore selected memory cells 12 by applying appropriate word line (WL)voltages and/or bit line (BL) voltages. For example, a source voltage(V_(sw“1”)) of approximately 2.5V may be applied to the source region 20(via, for example, the associated coupled source lines 30 _(i), 30_(i+1), 30 _(i+2), 30 _(i+3), 30 _(i+4), 30 _(i+5), 30 _(i+6), and 30_(i+7)) and a drain voltage (V_(dw“1”)) of approximately 0V may beapplied to the drain region 22 (via, for example, the associatedselected bit line 32 _(j) and 32 _(j+4)) of the memory transistor 14 ofthe memory cell 12 before a gate voltage (V_(gw“1”)) of approximately 0Vmay be applied to the gate 16 (via, for example, the associated selectedword line 28 _(i)), simultaneously thereto, or after the gate voltage(V_(gw“1”)) is applied to gate 16. It is preferred that the drainvoltage (V_(dw“1”)) include an amplitude which may be sufficient tomaintain a bipolar current that is suitable for programming the memorycell 12 to logic high (binary “1” data state). From a relative timingperspective, it is preferred that the drain voltage (V_(dw“1”)) mayextend beyond/after or continue beyond the conclusion of the gatevoltage (V_(gw“1”)), or extend beyond/after or continue beyond the timethe gate voltage (V_(gw“1”)) is reduced. Therefore, majority chargecarriers may be generated in the electrically floating body region 18via a bipolar current and majority charge carriers may accumulate (andbe stored) in a portion of the electrically floating body region 18 ofthe memory transistor 14 of the memory cell 12 that may be juxtaposed ornear the gate dielectric (which is disposed between the gate 16 and theelectrically floating body region 18).

Also illustrated in FIG. 5, an unselected holding drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory transistor 14 of the memory cell 12 before an unselectedholding gate voltage (V_(g-undisturb)) of approximately −1.0V may beapplied to the gate 16 (via, for example, the associated unselected wordline 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28 _(i+5), 28 _(i+6),and 28 _(i+7)), simultaneously thereto, or after the gate voltage(V_(g-undisturb)) is applied to gate 16.

FIG. 6 shows a diagram of voltage control signals to implement a writeoperation for logic low (binary “0” data state) into a memory cell inaccordance with an embodiment of the present disclosure. The temporallyvarying control signals that may be implemented to write logic low(binary “0” data state) may include a voltage applied to the gate 16(V_(gw“0”)), a voltage applied to the source 20 (V_(sw“0”)), and avoltage applied to the drain region 22 (V_(dw“0”)). For example, asource voltage (V_(sw“0”)) of approximately 2.5V may be applied to thesource region 20 (via, for example, the coupled source lines 30 _(i), 30_(i+1), 30 _(i+2), 3 _(i+3), 30 _(i+4), 30 _(i+5), 30 _(i+6), and 30_(i+7)) and a drain voltage of approximately 0.5V may be applied to thedrain region 22 (V_(dw“0”)), may be applied before a gate voltage(V_(gw“0”)) of approximately 0V is applied to the gate 16, orsimultaneously thereto, or after the gate voltage (V_(gw“0”)) is appliedto the gate 16. Particularly, the source to drain voltage(V_(sw“0”)-V_(dw“0”)) may include an amplitude which may be insufficientto maintain a bipolar current that is suitable for writing the memorycell 12 to logic high (binary “1” data state). From a relative timingperspective, it may be preferred that the drain voltage (V_(dw“0”)) mayextend beyond/after or continue beyond the conclusion of the gatevoltage (V_(gw“0”)), or extend beyond/after or continue beyond the timethe gate voltage (V_(gw“0”)) is reduced. For example, majority chargecarriers may be generated in the electrically floating body region 18via a bipolar current and majority charge carriers may be accumulated(and be stored) in a portion of the electrically floating body region 18of the memory transistor 14 of the memory cell 12 that is juxtaposed ornear the gate dielectric (which is disposed between the gate 16 and theelectrically floating body region 18).

Also illustrated in FIG. 6, an unselected masking drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory transistor 14 of the memory cell 12 before an unselecteddisturb reduction gate voltage (V_(g-undisturb)) of approximately −1.0Vmay be applied to the gate 16 (via, for example, the associatedunselected word line 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28_(i+5), 28 _(i+6), and 28 _(i+7),), simultaneously thereto, or after thegate voltage (V_(g-undisturb)) is applied to gate 16.

FIG. 7 shows a diagram of voltage control signals to implement a readoperation of a memory cell in accordance with an embodiment of thepresent disclosure. For example, read control signals may be applied tothe source region 20, the drain region 22 and the gate 16. A sourcevoltage (V_(sr)) of S approximately 2.5V and a drain voltage (V_(dr)) ofapproximately 0V may be applied to the source region 20 and the drainregion 22, respectively, before application of a gate voltage (V_(gr))of approximately −0.5V applied to the gate 16, simultaneously thereto,or after the gate voltage (V_(gr)) is applied to the gate 16. Further,the drain voltage (V_(dr)) may extend beyond/after or continue beyondthe conclusion of the gate voltage (V_(gr)), simultaneously thereto (asillustrated in FIG. 7), or before the gate voltage (V_(gr)) may concludeor cease.

Also illustrated in FIG. 7, an unselected masking drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory transistor 14 of the memory cell 12 before an unselecteddisturb reduction gate voltage (V_(g-undisturb)) of approximately −1.0Vmay be applied to the gate 16 (via, for example, the associatedunselected word line 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28_(i+5), 28 _(i+6), and 28 _(i+7)), simultaneously thereto, or after thegate voltage (V_(g-undisturb)) is applied to gate 16.

In an exemplary embodiment, during the read operation, a bipolar currentis generated in memory cells 12 storing logic high (binary “1” datastate) and little to no bipolar current is generated in memory cells 12storing logic low (binary “0” data state). The data state may bedetermined primarily by, sensed substantially using and/or basedsubstantially on the bipolar transistor current that is responsive tothe read control signals and significantly less by the interface channelcurrent component, which is less significant and/or negligiblerelatively to the bipolar component.

The writing and reading techniques described herein may be employed inconjunction with a plurality of memory cells 12 arranged in an array ofmemory cells. A memory array implementing the structure and techniquesof the present disclosures may be controlled and configured including aplurality of memory cells 12 having a common source line (SL) for eachrow of memory cells 12. The exemplary layouts or configurations(including exemplary control signal voltage values), in accordance toone or more exemplary embodiments of the present disclosure are shown,each consisting of the control signal waveforms and exemplary arrayvoltages during one-step writing and reading.

Accordingly, the illustrated/exemplary voltage levels to implement thewrite and read operations are merely exemplary. The indicated voltagelevels may be relative or absolute. Alternatively, the voltagesindicated may be relative in that each voltage level, for example, maybe increased or decreased by a given voltage amount (e.g., each voltagemay be increased or decreased by 0.5V, 1.0V and 2.0V) whether one ormore of the voltages (e.g., the source region voltage, the drain regionvoltage or gate voltage) become or are positive and negative.

Referring to FIG. 8, there is shown a schematic of a memory array 80implementing the structure and techniques having a common source line 30(SL) in accordance with an exemplary embodiment of the presentdisclosure. As mentioned above, the present disclosure may beimplemented in any memory array architecture having a plurality ofmemory cells 12 that employ memory transistors 14. For example, asillustrated in FIG. 8, a memory array implementing the structure andtechniques of the present disclosure may be controlled and configuredhaving a common source line (SL) for every two rows of memory cells 12(a row of memory cells 12 includes a common word line (WL)). Theplurality of memory cells 12 include a sub-array of memory cells 12 (forexample, 8×8 sub-array of memory cells 12 enclosed by the dotted line).The semiconductor DRAM device 10 may include data write and sensecircuitry 36 coupled to a plurality of bit lines (BL) 32 of theplurality of memory cells 12 (for example, 32 _(j), 32 _(j+1), 32_(j+2), 32 _(j+3), 32 _(j+4), 32 _(j+5), 32 _(j+6), and 32 _(j+7)).Also, the semiconductor DRAM device 10 may include memory cell selectionand control circuitry 38 coupled to one or more word lines (WL) 28 (forexample, 28 _(i), 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28 _(i+5),28 _(i+6), and 28 _(i+7)) and/or common source lines (SL) 30 (forexample, 30 _(i), 30 _(i+1), 30 _(i+2), and 30 _(i+3)). In an exemplaryembodiment, the source lines 30 (SL) (for example, 30 _(i), 30 _(i+1),30 _(i+2), 30 _(i+3), 30 _(i+4), 30 _(i+5), 30 _(i+6), and 30 _(i+7)) ofthe sub-array of memory cells 12 may be coupled together and driven by asource line driver 48 (e.g., inverter circuits and/or logic circuits).Although the source line driver 48 shown in FIG. 4, may be anindependent voltage driver, the source line driver 48 may be locatedwithin and/or integrated with the memory cell selection and controlcircuitry 38. An amount of space taken by source line drivers 48 in thesemiconductor DRAM device 10 may be reduced by coupling a plurality ofcommon source lines (SL) 30 of a sub-array of memory cells 12 to asingle source line driver 48.

As illustrated in FIG. 8, a sub-array of memory cells 12 of thesemiconductor DRAM device 10 may include eight rows by eight columns ofmemory cells 12 having a plurality of common source lines (SL) coupledto a single source line (SL) driver. It may be appreciated by oneskilled in the art that the sub-array of memory cells 12 having aplurality of common source lines 30 (SL) coupled to a single source line(SL) driver may be any size, for example, but not limited to, four rowsby four columns, sixteen rows by sixteen columns, thirty-two rows bythirty-two columns, sixty-four rows by sixty-four columns, etc.

An example (including exemplary control signal voltage values),according to certain aspects of the present disclosure may be also shownthat consists of the control signal waveforms and exemplary arrayvoltages during writing operation and/or reading operation. For example,the temporally varying control signals to implement the write operationmay include (i) a voltage (V_(sw)) applied to the source 20 via theassociated common coupled source lines (SL), (ii) a voltage (V_(gw))applied to the gate 16 via the associated word line (WL), and (iii) avoltage (V_(dw)) applied to the drain region 22 via the associated bitline (BL). The binary “1” or “0” data states may be written to one ormore selected memory cells 12 by applying appropriate word line (WL)voltages and/or bit line (BL) voltages.

FIG. 9 shows a diagram of voltage control signals to implement a writeoperation for logic high (binary “1” data state) into a memory cell inaccordance with an exemplary embodiment of the present disclosure. Thecontrol signals may be configured to reduce a number of source line (SL)drivers by coupling a plurality of common source lines (SL) to a singlesource line (SL) driver as well as a write operation whereby selectedmemory cells 12 of a selected row of memory cells 12 may be selectivelywritten or programmed to either logic high (binary “1” data state) orlogic low (binary “0” date state) without first implementing a “clear”operation. For example, the temporally varying control signals toimplement the write logic high (binary “1” data state) operation includethe voltage applied to the gate 16 (V_(gw“1”)), the voltage applied tothe source region 20 (V_(sw“1”)), and the voltage applied to the drainregion 22 (V_(dw“1”)). The binary “1” data state may be written to oneor more selected memory cells 12 by applying appropriate word line (WL)voltages and/or bit line (EL) voltages. For example, a source voltage(V_(sw“1”)) of approximately 2.5V may be applied to the source region 20(via, for example, the associated coupled common source lines 30 _(i),30 _(i+1), 30 _(i+2), and 30 _(i+3)) and a drain voltage (V_(dw“1”)) ofapproximately 0V may be applied to the drain region 22 (via, forexample, the associated selected bit line 32 _(j) and 32 _(j+4)) of thememory transistor 14 of the memory cell 12 before a gate voltage(V_(gw“1”)) of approximately 0V may be applied to the gate 16 (via, forexample, the associated selected word line 28 _(i)), simultaneouslythereto, or after the gate voltage (V_(gw“1”)) is applied to gate 16. Itis preferred that the drain voltage (V_(dw“1”)) include an amplitudewhich may be sufficient to maintain a bipolar current that is suitablefor programming the memory cell 12 to logic high (binary “1” datastate). From a relative timing perspective, it is preferred that thedrain voltage (V_(dw“1”)) may extend beyond/after or continue beyond theconclusion of the gate voltage (V_(gw“1”)), or extend beyond/after orcontinue beyond the time the gate voltage (V_(gw“1”)) is reduced.Therefore, majority charge carriers may be generated in the electricallyfloating body region 18 via a bipolar current and majority chargecarriers may accumulate (and be stored) in a portion of the electricallyfloating body region 18 of the memory transistor 14 of the memory cell12 that may be juxtaposed or near the gate dielectric (which is disposedbetween the gate 16 and the electrically floating body region 18).

Also illustrated in FIG. 9, an unselected masking drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory transistor 14 of the memory cell 12 before an unselecteddisturb reduction gate voltage (V_(g-undisturb)) of approximately −1.0Vmay be applied to the gate 16 (via, for example, the associatedunselected word line 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28_(i+5), 28 _(i+6), and 28 _(i+7)), simultaneously thereto, or after thegate voltage (V_(g-undisturb)) is applied to gate 16.

FIG. 10 shows a diagram of voltage control signals to implement a writeoperation for logic low (binary “0” data state) into a memory cell inaccordance with an embodiment of the present disclosure. The temporallyvarying control signals that may be implemented to write logic low(binary “0” data state) may include a voltage applied to the gate 16(V_(gw“0”)) a voltage applied to the source 20 (V_(gw“0”)), and avoltage applied to the drain region 22 (V_(dw“0”)). For example, asource voltage (V_(sw“0”)) of approximately 2.5V may be applied to thesource region 20 (via, for example, the associated coupled common sourcelines 30 _(i), 30 _(i+1), 30 _(i+2), and 30 _(i+3)) and a drain voltageof approximately 0.5V may be applied to the drain region 22 (V_(dw“0”)),may be applied before a gate voltage (V_(gw“0”)) of approximately 0V isapplied to the gate 16, or simultaneously thereto, or after the gatevoltage (V_(gw“0”)) is applied to the gate 16. Particularly, the sourceto drain voltage (V_(sw“0”)-V_(dw“0”)) may include an amplitude whichmay be insufficient to maintain a bipolar current that is suitable forwriting the memory cell 12 to logic high (binary “1” data state). From arelative timing perspective, it may be preferred that the drain voltage(V_(dw“0”)) may extend beyond/after or continue beyond the conclusion ofthe gate voltage (V_(gw“0”)), or extend beyond/after or continue beyondthe time the gate voltage (V_(gw“0”)) is reduced. For example, majoritycharge carriers may be generated in the electrically floating bodyregion 18 via a bipolar current and majority charge carriers may beaccumulated (and be stored) in a portion of the electrically floatingbody region 18 of the memory transistor 14 of the memory cell 12 that isjuxtaposed or near the gate dielectric (which is disposed between thegate 16 and the electrically floating body region 18).

Also illustrated in FIG. 10, an unselected masking drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory transistor 14 of the memory cell 12 before an unselecteddisturb reduction gate voltage (V_(g-undisturb)) of approximately −1.0Vmay be applied to the gate 16 (via, for example, the associatedunselected word line 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28_(i+5), 28 _(i+6), and 28 _(i+7)), simultaneously thereto, or after thegate voltage (V_(g-undisturb)) is applied to gate 16.

FIG. 11 shows a diagram of voltage control signals to implement a readoperation of a memory cell in accordance with an embodiment of thepresent disclosure. For example, read control signals may be applied tothe source region 20, the drain region 22 and the gate 16. A sourcevoltage (V_(sr)) of approximately 2.5V and a drain voltage (V_(dr)) ofapproximately 0V may be applied to the source region 20 and the drainregion 22, respectively, before application of a gate voltage (V_(gr))of approximately −0.5V applied to the gate 16, simultaneously thereto,or after the gate voltage (V_(gr)) is applied to the gate 16. Further,the drain voltage (V_(dr)) may extend beyond/after or continue beyondthe conclusion of the gate voltage (V_(gr)), simultaneously thereto (asillustrated in FIG. 11), or before the gate voltage (V_(gr)) mayconclude or cease.

Also illustrated in FIG. 11, an unselected masking drain voltage(V_(d-undisturb)) of approximately 1.0V may be applied to the drainregion 22 (via, for example, the associated unselected bit line 32_(j+1), 32 _(j+2), 32 _(j+3), 32 _(j+5), 32 _(j+6), and 32 _(j+7)) ofthe memory is transistor 14 of the memory cell 12 before an unselecteddisturb reduction gate voltage (V_(g-undisturb)) of approximately −1.0Vmay be applied to the gate 16 (via, for example, the associatedunselected word line 28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28_(i+5), 28 _(i+6), and 28 _(j+7)), simultaneously thereto, or after thegate voltage (V_(g-undisturb)) is applied to gate 16.

In an exemplary embodiment, during the read operation, a bipolar currentis generated in memory cells 12 storing logic high (binary “1” datastate) and little to no bipolar current is generated in memory cells 12storing logic low (binary “0” data state). The data state may bedetermined primarily by, sensed substantially using and/or basedsubstantially on the bipolar transistor current that is responsive tothe read control signals and significantly less by the interface channelcurrent component, which is less significant and/or negligible relativeto the bipolar component.

The writing and reading techniques described herein may be employed inconjunction with a plurality of memory cells 12 arranged in an array ofmemory cells. A memory array implementing the structure and techniquesof the present disclosures may be controlled and configured including aplurality of memory cells 12 having a common source line (SL) for tworows of memory cells 12. The exemplary layouts or configurations(including exemplary control signal voltage values), in accordance toone or more exemplary embodiments of the present disclosure are shown,each consisting of the control signal waveforms and exemplary arrayvoltages during one-step writing and reading.

Accordingly, the illustrated/exemplary voltage levels to implement thewrite and read operations are merely exemplary. The indicated voltagelevels may be relative or absolute. Alternatively, the voltagesindicated may be relative in that each voltage level, for example, maybe increased or decreased by a given voltage amount (e.g., each voltagemay be increased or decreased by 0.5V, 1.0V and 2.0V) whether one ormore of the voltages (e.g., the source region voltage, the drain regionvoltage or gate voltage) become or are positive and negative.

FIG. 12 shows a diagram of voltage control signals to implement a writeoperation, a read operation, a refresh operation and/or an inhibitoperation into a memory cell in accordance with an embodiment of thepresent disclosure. FIG. 12 illustrates, a write/read phase and arefresh/inhibit phase of voltage control signals. As described above,during a write operation and/or a read operation, one or more voltagecontrol signals may be applied to the semiconductor DRAM device 10 toimplement a write operation and/or a read operation of a plurality ofmemory cells 12 (for example, memory cells 12 a and 12 e, shown in FIGS.4 and 8) having a plurality of source lines (SL) coupled to a singlesource line (SL) driver.

After performing a write operation and/or a read operation of aplurality of memory cells 12 (for example, memory cells 12 a and 12 e,shown in FIGS. 4 and 8), it may be advantageous to employ a refreshoperation to the neighboring memory cells 12. Thus, with reference toFIGS. 4 and 8, where the write operation and/or the read operation isconducted on the row of memory cells 12 associated with word line 28_(i), the neighboring rows of memory cells 12 associated with word lines28 _(i+1), 28 _(i+2), 28 _(i+3), 28 _(i+4), 28 _(i+5), 28 _(i+6), and/or28 _(i+7), may be refreshed.

In an exemplary embodiment, the temporally varying control signals thatmay be implemented to refresh a plurality of memory cells 12 may includemaintaining a voltage applied to the source 20 (V_(sw/r)) during a writeoperation and/or a read operation, a voltage applied to the gate 16(V_(g-refresh)), and a voltage applied to the drain region 22(V_(d-refresh)). For example, the source voltage (V_(sw/r)) applied tothe source region 20 may be maintained at approximately 2.5V (via, forexample, the associated source lines 30 of a sub-array of memory cells12), a drain voltage of approximately 0V may be applied to the drainregion 22 (V_(d-refresh)), and a gate voltage (V_(g-refresh)) ofapproximately −0.5V is applied to the gate 16.

For example, in the event that logic high (binary “1” data state) isstored in the memory cell 12, the refresh voltage may cause majoritycharge carriers to generate in the electrically floating body region 18via a bipolar current and majority charge carriers may be reinforced bythe refresh voltage in the electrically floating body region 18 of thememory transistor 14 of the memory cell 12. In the event that a logiclow (binary “0” data state) is stored in the memory cell 12, the refreshvoltage may not cause majority charge carriers to generate in theelectrically floating body region 18, thus the logic low (binary “0”data state) may remain stored in the memory cell 12.

In another exemplary embodiment, the temporally varying control signalsthat may be implemented to inhibit a writing operation and/or a readingoperation to a plurality of memory cells 12 may include maintaining thevoltage applied to the source 20 (V_(sw/r)) during a writing operationand/or a reading operation, a voltage applied to the gate 16(V_(g-inhibit)), and a voltage applied to the drain region 22(V_(d-inhibit)). For example, the source voltage (V_(sw/r)) applied tothe source region 20 may be maintained at approximately 2.5V (via, forexample, the associated source lines 30 of a sub-array of memory cells12), a drain voltage of approximately 1V may be applied to the drainregion 22 (V_(d-inhibit)), and a gate voltage (V_(g-inhibit)) ofapproximately −1.0V may be applied to the gate 16.

Also, a sub-array of memory cells 12 (shown in FIGS. 4 and 8) of thesemiconductor DRAM device 10 including a plurality of memory cells 12may be divided into a plurality of sections. Each section of thesub-array of memory cells may include a sub-group of a plurality ofsource lines 30 (SL) (for example, two source lines or four sourcelines) associated with the sub-array of memory cells 12 coupled to asingle source line (SL) driver. For example, a sub-array of memory cells12 of the semiconductor DRAM device 10 may include eight source lines(SL) coupled to a single source line (SL) driver. Each section of thesub-array of memory cells 12 may include two source lines 30 (SL) orfour source lines 30 (SL) of the eight source lines 30 (SL) of thesub-array of memory cells 12. Also, each section of the plurality ofsections may perform different operations (for example, write operation,read operation, refresh operation, and/or inhibit operation). Forexample, a first section of the plurality of sections (for example,memory cells 12 associated with word lines (WL) 28 _(i), 28 _(i+1), 28_(i+2), and 28 _(i+3)) may perform a refresh function, while a secondsection of the plurality of sections (for example, memory cells 12associated with word lines (WL) 28 _(i+4), 28 _(i+5), 28 _(i+6), and 28_(i+7)) may perform an inhibit function.

At this point it should be noted that simultaneously driving a pluralityof source line (SL) in accordance with the present disclosure asdescribed above typically involves the processing of input data and thegeneration of output data to some extent. This input data processing andoutput data generation may be implemented in hardware or software. Forexample, specific electronic components may be employed in asemiconductor DRAM device or similar or related circuitry forimplementing the functions associated with simultaneously driving aplurality of source line (SL) in accordance with the present disclosureas described above. Alternatively, one or more processors operating inaccordance with instructions may implement the functions associated withsimultaneously driving a plurality of source lines (SL) in accordancewith the present disclosure as described above. If such is the case, itis within the scope of the present disclosure that such instructions maybe stored on one or more processor readable media (e.g., a magnetic diskor other storage medium), or transmitted to one or more processors viaone or more signals embodied in one or more carrier waves.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are intended to fall within the scope ofthe present disclosure. Further, although the present disclosure hasbeen described herein in the context of a particular implementation in aparticular environment for a particular purpose, those of ordinary skillin the art will recognize that its usefulness is not limited thereto andthat the present disclosure may be beneficially implemented in anynumber of environments for any number of purposes. Accordingly, theclaims set forth below should be construed in view of the full breadthand spirit of the present disclosure as described herein.

1. An apparatus for simultaneously driving a plurality of source linescomprising: a plurality of source lines coupled to one or more sourceline drivers, wherein the plurality of source lines are divided into aplurality of sub-groups of source lines and each of the plurality ofsub-groups of source lines is configured to perform differentoperations; and a plurality of dynamic random access memory cellsarranged in an array of rows and columns, each dynamic random accessmemory cell including one or more memory transistors having: a firstregion coupled to a first source line of the plurality of source lines;a second region coupled to a bit line; a body region disposed betweenthe first region and the second region, wherein the body region iselectrically floating; and a gate coupled to a word line and spacedapart from, and capacitively coupled to, the body region.
 2. Theapparatus according to claim 1, wherein a total number of source linescoupled to the one or more source line drivers is based at least in parton power consumption of the plurality of dynamic random access memorycells.
 3. The apparatus according to claim 1, wherein a total number ofsource lines coupled to the one or more source line drivers is based atleast in part on disturbance on the plurality of dynamic random accessmemory cells.
 4. The apparatus of claim 1, wherein a total number ofsource lines coupled to the one or more source line drivers is based atleast in part on an available area on a circuit board.
 5. The apparatusaccording to claim 1, wherein each row of the plurality of dynamicrandom access cells is coupled to one source line of the plurality ofsource lines.
 6. The apparatus according to claim 1, wherein multiplerows of the plurality of dynamic random access memory cells are coupledto one source line of the plurality of source lines.
 7. The apparatusaccording to claim 1, wherein at least one of four source lines, eightsource lines, sixteen source lines, or thirty-two source lines arecoupled to the one or more source line drivers.
 8. The apparatusaccording to claim 1, wherein the different operations comprise at leastone of a write operation, a read operation, a refresh operation, and aninhibit operation.
 9. The apparatus according to claim 1, wherein eachof the plurality of sub-groups of source lines is coupled to arespective one of the one or more source line drivers.
 10. A method forsimultaneously driving a plurality of source lines comprising the stepsof: coupling a plurality of source lines to one or more source linedrivers, wherein the plurality of source lines are divided into aplurality of sub-groups of source lines and each of the plurality ofsub-groups of source lines is configured to perform differentoperations; and arranging a plurality of dynamic random access memorycells in an array of rows and columns, each dynamic random access memorycell including one or more memory transistors having: a first regioncoupled to a first source line of the plurality of source lines; asecond region coupled to a bit line; a body region disposed between thefirst region and the second region, wherein the body region iselectrically floating; and a gate coupled to a word line and spacedapart from, and capacitively coupled to, the body region.
 11. The methodaccording to claim 10, further comprising coupling each row of theplurality of dynamic random access cells to one source line of theplurality of source lines.
 12. The method according to claim 10, furthercomprising coupling multiple rows of the plurality of dynamic randomaccess memory cells to one source line of the plurality of source lines.13. The method according to claim 10, wherein coupling a plurality ofsource lines to one or more source line drivers comprises coupling atleast one of four source lines, eight source lines, sixteen sourcelines, or thirty-two source lines to the one or more source linedrivers.
 14. The method according to claim 10, wherein the differentoperations comprise at least one of a write operation, a read operation,a refresh operation, and an inhibit operation.
 15. The method accordingto claim 10, wherein each of the plurality of sub-groups of source linesis coupled to a respective one of the one or more source line drivers.